Method end and apparatus for producing a product-filled container

ABSTRACT

A method for manufacturing a container filled with a product is disclosed. The container has a substantially tubular body portion of thin-walled plastic or laminated plastic material and a butt-weldable end-piece at each end of the body portion. A first end-piece is fitted to one end of the body portion and the product is introduced into the container via the open end of the body portion, a second end-piece 13 is introduced into the open body portion end to an intermediate position at which it partially projects into the body portion, and the plastic material of the body portion end region and the second end-piece is softened through application of heat energy. The end-piece by means of relative displacement between it and the body portion, is pressed into the body portion to its terminal position during evacuation of air from the interior of the container via an opening in the end-piece and the opening is thereafter heat-sealed.

TECHNICAL FIELD

The present invention relates to a method, end-piece and apparatus forproducing a product-filled container, the container comprising asubstantially tubular body portion of thin-walled plastic or laminatedplastic material, a first butt-weldable end-piece at a first end of thebody portion and a second butt-weldable end-piece at a second end of thebody portion.

BACKGROUND

Tubes and bottles made from thin-walled plastic or plastic laminatedmaterial are used for packaging of, for example, creams, ointments andvarious other viscous chemical/engineering preparations. Swedish PatentApplication 8800548-3 describes an end-piece and a method formanufacturing tubes or bottles by butt-welding an end-piece in both endsof a tubular-shaped body portion of thin-walled plastic or laminatedplastic material.

The advantage of manufacturing tubes or bottles in this way is that theneed to transport bulky empty containers over long distances is avoided.Accordingly the method allows the private packager to produce his owntubes or bottles without comprehensive equipment.

The tube or bottle produced according to the above method can be filledwith its product via its opening, after which a cap is affixed over theopening with the aid of, for example, screw threads.

In many cases, however, it is desirable to provide a container which hasbeen sealed in a controlled environment so that the customer can confirmthat the packaging is unopened. This results in enhanced quality, bothfor the packaging and its contents.

During production of such a sealed container it is advantageous thatfilling with the product occurs between the fitting of the firstend-piece, preferably tubularly formed, and the second end-piece. Ithas, however, proven to be difficult to fit the second end-piece withoutthe product in the body-portion open end fouling either the weld-seam orthe sealing region. A contributory factor to this problem is, of course,the high production rate which can reach around two units per second.

It is possible to avoid this problem by increasing the so-called"head-space" volume between the product and the inner surface of theend-piece. This can, however, lead to negative consequences for theproduct if there is the risk that it can react with the air in the saidhead-space. Furthermore, the customer may discriminate against acontainer with a large head space volume since it does not appear to becompletely full.

SUMMARY OF THE INVENTION

The object of the present invention is thus to provide a method and adevice which permits the production of full containers at a high rateand with minimal head-space volume.

This object is achieved in accordance with the present invention by amethod for manufacturing a container filled with a product, thecontainer comprising a substantially tubular body portion of thin-waledplastic or laminated plastic material, a first butt-weldable end-pieceat a first end of the body portion and a second butt-weldable end-pieceat a second end of the body portion, the method comprising:

fitting said first end-piece to said first end of the body portion;

introducing the product into the container via said second end of thebody portion;

introducing said second end-piece into said second end of the bodyportion to an intermediate position at which the second end-piecepartially projects into the body portion,

softening the plastic material of an end region of the body portion andthe second end-piece through application of heat energy;

pressing the second end-piece into the body portion to a terminalposition by means of relative displacement between the second end-pieceand the body portion during evacuation of air from within the containervia an opening in the second end-piece; and

heat-sealing said opening.

The invention also provides a device for butt-welding an end-piecehaving a substantially cylindrical wall region to a substantiallytubular body portion of thin-walled plastic or laminated plasticmaterial to form a container, said device comprising:

application means for placing said end-piece in a defined intermediateposition, partially projecting into an end of the tubular body portion;

heating means for supplying warm gas to soften the plastic material of aweld region of the body portion and a region or regions of an outwardlyprojecting portion of the end-piece;

means for displacing the body portion and the end-piece relative to eachother until the end-piece is in its terminal position in the bodyportion; and

suction means for evacuating utilized warm air from the weld region andexcess air from the container via an evacuation nipple in the end-piece.

Further advantageous embodiments are detailed in the respectivedependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail in the following, withreference to the drawings in which

FIGS. 1 and 2 schematically show the application of an end-piece to atubular body portion in two steps with a device according to theinvention,

FIG. 3 shows the sealing of an evacuation opening in the end-piece,

FIG. 4 shows the end-piece after said sealing, and

FIG. 5 shows the compression of the weld-seam.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The flattenable tubular body portion 10 shown in the drawings can bemade from a single-layer plastic material or from a laminate comprisinga metal foil which provides the body portion with better barrierproperties. The body portion can be produced by a foil butt-seam welderor, alternatively, from an extruded tube, cut to the appropriate lengthSuch body portions normally have a wall thickness well under 1 mm.

In the drawings only the upper end of the body portion is shown. Thelower part of the body portion is already fitted with an end-piece inthe form of, for example, a discharge outlet with cooperating screw cap.The body portion is filled via its open end with a product 11 to apredetermined level which corresponds to the desired quantity for thecontainer. The body portion is now placed vertically with the openingupwards in a cylindrical holder 12 in a (not shown) rotary indexingtable which is provided with means for fitting the end-piece in thefollowing sequence of steps.

In FIG. 1 the end-piece 13 has been partially introduced into theupwardly open body portion end and then advanced one stage to thewelding station shown in FIGS. 1 and 2.

The end-piece 13 comprises an insert section 14 which, on the inner end,is provided with a transverse wall 15 and, on the other end, is providedby a U-shaped section 16. The insert section 14 tapers inwardly towardsthe transverse wall 15. The U-shaped section is provided with a groovethat tapers towards the bottom of the U-shaped section.

The end-piece can, by way of example, be produced by injection-molding,whereby a barrier foil blank may be included on the inner side or theouter side of the transverse wall 15.

The welding station is provided with passages 17 for supplying hot gasvia directed openings to the region of the body portion end edge and tothe groove in the U-shaped section 16 in order to soften these regionsby application of heat to a temperature between about 300°-500° C. Aftersuitable heating, the holder 12 is displaced upwardly in the weldingapparatus so that the end-piece 13 is pressed into the tubular bodyportion until the rim of the body portion meets with the bottom of thegroove, as shown in FIG. 2. A central nozzle head 18 serves as anabutment for the endpiece 13.

The nozzle head 18 is formed with a substantially flat underside whichis provided with a central recess 19, intended to receive with generousclearance an evacuation nipple 20 centrally located on the end-piece'stransverse wall. The nipple 20 permits the evacuation of air from thehead-space between the product 11 and the end wall 15 when the end-pieceis pressed into the body portion end. For this purpose the recess 19 isequipped with a branch conduit 21 which exits into a space 22surrounding the nozzle head 18.

In a preferred embodiment of the invention the underside of the nozzlehead 18 is also provided with a groove 23 which extendscircumferentially above the perimeter of the transverse wall 15. Abranch conduit 24 for the supply of cooling gas opens into the groove 23and accordingly distributes cooling gas around the perimeter of thetransverse wall 15. In this way the transverse wall is cooled withoutaffecting the heating of the overlapping wall region of the body portionvia the passages 17. Such a cooling means is described and claimed inour co-pending application "Method and Apparatus for controlling thetemperature of a container end portion during manufacture".

A suitable cooling gas can be cold air. Expended cold air flows from thegroove 23 via the underside of the nozzle head to the surrounding space22 from where the utilized cold air and hot gas is drawn from thewelding station via passages 25. Since the recess 19 accommodates theevacuation nipple 20 with generous clearance, there is no risk of anyquantity of the viscous product being sucked out through the nipple.

FIG. 5 shows the subsequent step of compressing the U-shaped section 16whilst still soft so that a seal in this region is achieved. Compressioncan be carried out by a vertically displaceable abutment 26 and aplurality of horizontal compression devices 27. These compressiondevices may be mechanically or elastic-hydraulically operable.

FIGS. 3 and 4 show how the evacuation nipple is sealed by means of avertically displaceable heated mandrel 28 which is provided with aheating element 29 connected via a cable 30 to an electrical source. Theheated mandrel 28 is mounted on an arm 31, vertically displaceable via apiston cylinder 32. As is shown in FIG. 4, the evacuation nipple is thustransformed into a closed nipple 33.

The invention is not restricted to the above described embodiments, butmay be modified within the scope of the appended claims.

I claim:
 1. A method for manufacturing a container filled with aproduct, the container comprising a substantially tubular body portionof thin-walled plastic or laminated plastic material, a firstbutt-weldable end-piece at a first end of the body portion and a secondbutt-weldable end-piece at a second end of the body portion, the methodcomprising:fitting said first end-piece to said first end of the bodyportion; introducing the product into the container via said second endof the body portion; introducing said second end-piece into said secondend of the body portion to an intermediate position at which the secondend-piece partially projects into the body portion, softening theplastic material of an end region of the body portion and the secondend-piece through application of heat energy; pressing the secondend-piece into the body portion to a terminal position by means ofrelative displacement between the second end-piece and the body portionduring evacuation of air from within the container via an opening in thesecond end-piece; and heat-sealing said opening.
 2. The method asclaimed in claim 1, wherein the heat energy is provided by a hot gas. 3.The method as claimed in claim 1 or 2, wherein the weld seams betweenthe tubular body portion and the second end-piece are subjected topinching together.
 4. The method as claimed in claim 2, wherein duringthe introduction of said second end-piece into the body portion aquantity of cooling gas is provided to a region of said second end-pieceadjacent the product.
 5. A method for manufacturing a container filledwith a product, the container comprising a substantially tubular bodyportion of thin-walled plastic or laminated plastic material having afirst end and a second end, and a butt-weldable end-piece at said firstend of said body portion, the method comprising the steps of:fittingsaid butt-weldable end-piece to said first end of said body portion;placing the product into the container through said first end of saidbody portion; placing said butt-weldable end-piece adjacent said firstend of said body portion; applying heat to at least a portion of saidbutt-weldable end-piece to soften the plastic material thereof;evacuating air present within the container between the product placedtherein and said butt-weldable end-piece through an opening in saidbutt-weldable end-piece; pressing said butt-weldable end-piece into saidbody portion to a terminal position between said first end and saidsecond end thereof by means of relative displacement between saidbutt-weldable end-piece and said body portion during said evacuation ofair through the opening in said butt-weldable end-piece; and applyingheat to the opening in said butt-weldable end-piece to seal the opening.6. The method of claim 5 wherein said heat applied during said step ofapplying heat to at least a portion of said butt-weldable end-piece tosoften the plastic material thereof, is a hot gas.
 7. The method ofclaim 5 wherein said step of placing said butt-weldable end-pieceadjacent said first end of said body portion further comprises the stepof placing said butt-weldable end-piece at least partially within saidbody portion to an intermediate position between said first end and saidsecond end thereof.
 8. The method of claim 7 further comprising the stepof providing a quantity of cooling gas to at least a portion of saidbutt-weldable end-piece during placement of said butt-weldable end-pieceto the terminal position within said body portion.
 9. A device forbutt-welding an end-piece having a substantially cylindrical wall regionto a substantially tubular body portion of thin-walled plastic orlaminated plastic material to form a container, said devicecomprising:application means for placing said end-piece in a definedintermediate position, partially projecting into an end of the tubularbody portion; heating means for supplying warm gas to soften the plasticmaterial of a weld region of the body portion and a region or regions ofan outwardly projecting portion of the end-piece; means for displacingthe body portion and the end-piece relative to each other until theend-piece is in its terminal position in the body portion; and suctionmeans for evacuating utilized warm air from the weld region and excessair from the container via an evacuation nipple in the end-piece. 10.The device as claimed in claim 9, wherein means are provided forsupplying a cooling gas to an end wall of the end-piece.
 11. The deviceas claimed in claim 10, wherein the suction means is adapted to removeutilized cooling gas from the end wall.
 12. The device as claimed inclaim 10 or 11, wherein the means for supplying cooling gas to the endwall and the suction means form an integral component for introducingthe end-piece into the end of the body portion.
 13. The device asclaimed in claim 10, wherein the means for supplying cooling gas opensinto a ring-shaped groove which runs above and substantially around aperimeter of the end wall.